Chronic neurodegeneration by aflatoxin B1 depends on alterations of brain enzyme activity and immunoexpression of astrocyte in male rats

Ecotoxicol Environ Saf. 2019 Oct 30:182:109407. doi: 10.1016/j.ecoenv.2019.109407. Epub 2019 Jul 4.

Abstract

Aflatoxin B1 poses the greatest risk among the mycotoxins to target-organisms particularly human, however, no studies addressed the neurotoxicity of chronic exposure of aflatoxin. The oral dose level 1/600th of LD50 for 30, 60, and 90 days was used for three aflatoxin groups, respective to negative and vehicle control groups. Activity levels of brain antioxidants viz: superoxide dismutase, catalase, glutathione, and glutathione peroxidase significantly decreased in the three experimental durations in time-dependent trend, in contrast, lipid peroxidation showed a significant increase compared to controls. Significantly, chronic-dependent increase trend was noticed in the AF60 and AF90 group for acid phosphatase (16.1%, 35.2%), alkaline phosphatase (32.1%, 50.8%), aspartate aminotransferase (38.7%, 120.0%) and lactate dehydrogenase (30.6%, 42.1%) activities, respectively. However, a significant 23.7% decrease in the brain creatine kinase activity following 90 days of AFB1administration. Chronic administration of aflatoxin also causes alterations in activities of protein carbonyl with a maximum increase (twofold) after 90 days. Further, histopathological and immunohistochemical results confirmed time-related vasodilation, necrosis and astrocytes gliosis by high glial fibrillary acidic protein immunostaining in response to AFB1. These findings infer that long-term exposure to AFB1 results in several pathophysiological circumstances in a duration-dependent manner concerning neurodegeneration especially Alzheimer's disease.

Keywords: Aflatoxin; Antioxidants; Brain enzymes; Glial fibrillary acid protein; Neurodegeneration.

MeSH terms

  • Aflatoxin B1 / toxicity*
  • Animals
  • Antioxidants / metabolism
  • Astrocytes / drug effects*
  • Astrocytes / immunology
  • Astrocytes / pathology
  • Brain / drug effects*
  • Brain / enzymology*
  • Brain / pathology
  • Dose-Response Relationship, Drug
  • Environmental Pollutants / toxicity*
  • Glial Fibrillary Acidic Protein / biosynthesis
  • Immunohistochemistry
  • Lipid Peroxidation / drug effects
  • Male
  • Oxidative Stress* / drug effects
  • Oxidative Stress* / immunology
  • Rats
  • Rats, Wistar
  • Time Factors
  • Toxicity Tests, Chronic

Substances

  • Antioxidants
  • Environmental Pollutants
  • Glial Fibrillary Acidic Protein
  • Aflatoxin B1